1. Field of the Invention
Exemplary embodiments of the present disclosure relate to an airfield lighting system, and more particularly to an airfield lighting system configured to efficiently detect a defect of an LED lamp.
2. Description of Related Art
Generally, airfield lighting systems are aviation safety facilities used for directing airplanes during landing, take-off and taxiing. These lighting systems have a large number of light sources and it is important they are operated properly and that failed light sources are replaced quickly, especially during times of low visibility. Otherwise, the consequences of a plane missing a taxiway or a stop signal can be disastrous.
Although an aircraft pilot performs most of aircraft manipulations and collects information relying on visual and audio senses, most of the information is collected by eyes such that airfield lighting is very important in terms of its function.
Although conventional airfield lighting systems largely use halogen lamps, the halogen lamps are disadvantageous in that the lamps are low in efficiency and generate a large quantity of heat, albeit being advantageous in terms of miniaturization and color rendering.
Concomitant with global requirement on high energy efficiency in response to demand on highly efficient devices, lighting industries pay attention to LEDs (Light Emitting Devices), one of next generation light sources excellent in energy saving effect over conventional light sources and capable of being permanently used.
LEDs offer many advantages over conventional halogen lamps or incandescent lights, which are driving the adoption of same. These advantages include but are not limited to high energy efficiency, long lifetime, low maintenance cost, enhanced reliability and durability, as well as no lumen loss induced by filtering. As a result, the LEDs are widely used recently by replacing various lighting sources including halogen lamps, incandescent electric bulbs and fluorescent lamps. In response to this trend, aviation industries also participated in demands on savings in energy and maintenance/repair costs by replacing halogen lamps with LED lamps.
Meanwhile, ILCMS (Individual Lamp Control and Monitoring System) is a system configured to control ON/OFF of airfield lighting system on runways and taxiways, and to monitor airfield lighting state. The airfield lighting system uses a constant current source having a single loop. At this time, several scores to several hundreds of lamps are disposed from a CCR (Constant Current Regulator) to a final end of an airfield, and length of electric lines connecting the lamps ranges from several kilometers to several hundred kilometers. The airfield lighting electric source formed with a single loop supplies an electric power to electronic circuits for operation of a secondary lamp and ILCMS through a transformer having a current transformer characteristic.
At airports, communications are wirelessly performed between aircraft pilots and a control tower, such that wired communication is preferred to avoid interference by other wireless communication. It is difficult to newly install lines at existing airports, and therefore, application of power cable communication is essential for individual lamp control and monitoring system for airfield lighting system.
Under this circumstance, in a case LED lamps are used for the airfield lighting system, there is a problem in that defects of lighting lamps used for the existing airfield lighting facilities cannot be detected. Thus, technical development for efficiently detecting defects of LED lamps is necessary even if the LED lamps are used for airfield lighting system.